Complex adhesive boundaries for touch sensors

ABSTRACT

In one embodiment, an apparatus includes a cover panel. An adhesive layer is coupled to the cover panel. A perimeter of the adhesive layer forms at least a portion of a gasket seal extending substantially perpendicular to an inner surface of the cover panel. An inner surface of the gasket seal defines an edge of a channel. The apparatus also includes a substrate coupled to the adhesive layer. The substrate includes an outer surface having disposed thereon a connection pad region and drive or sense electrodes. The drive or sense electrodes are disposed between the substrate and the cover panel. At least a portion of the channel is disposed between the gasket seal and the connection pad region. The apparatus further includes a flexible printed circuit (FPC) electrically coupled by the connection pad region to the drive or sense electrodes. A first portion of the FPC extends through the channel.

RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.13/536,172 filed Jun. 28, 2012.

TECHNICAL FIELD

This invention relates generally to a touch sensor, and moreparticularly to complex adhesive boundaries for touch sensors.

BACKGROUND OF THE INVENTION

A touch sensor may detect the presence and location of a touch or theproximity of an object (such as a user's finger or a stylus) within atouch-sensitive area of the touch sensor overlaid on a display screen,for example. In a touch-sensitive-display application, the touch sensormay enable a user to interact directly with what is displayed on thescreen, rather than indirectly with a mouse or touch pad. A touch sensormay be attached to or provided as part of a desktop computer, laptopcomputer, tablet computer, personal digital assistant (PDA), smartphone,satellite navigation device, portable media player, portable gameconsole, kiosk computer, point-of-sale device, or other suitable device.A control panel on a household or other appliance may include a touchsensor.

There are a number of different types of touch sensors, such as (forexample) resistive touch screens, surface acoustic wave touch screens,and capacitive touch screens. Herein, reference to a touch sensor mayencompass a touch screen, and vice versa, where appropriate. When anobject touches or comes within proximity of the surface of thecapacitive touch screen, a change in capacitance may occur within thetouch screen at the location of the touch or proximity. A touch-sensorcontroller may process the change in capacitance to determine itsposition on the touch screen.

SUMMARY OF THE INVENTION

In one embodiment, an apparatus includes a cover panel. An adhesivelayer is coupled to the cover panel. A perimeter of the adhesive layerforms at least a portion of a gasket seal extending substantiallyperpendicular to an inner surface of the cover panel. An inner surfaceof the gasket seal defines an edge of a channel. The apparatus alsoincludes a substrate coupled to the adhesive layer. The substrateincludes an outer surface having disposed thereon a connection padregion and drive or sense electrodes. The drive or sense electrodes aredisposed between the substrate and the cover panel. At least a portionof the channel is disposed between the gasket seal and the connectionpad region. The apparatus further includes a flexible printed circuit(FPC) electrically coupled by the connection pad region to the drive orsense electrodes. A first portion of the FPC extends through the channelin a direction substantially perpendicular to the inner surface of thecover panel and substantially parallel to the inner surface of thegasket seal.

In another embodiment, an apparatus includes a cover panel, first andsecond adhesive layers, a substrate, and dielectric layer, and aflexible printed circuit (FPC). The first optically clear adhesive layeris coupled to the cover panel. The substrate is coupled to the firstadhesive layer and comprises outer and inner surfaces, the outer andinner surfaces of the substrate being on opposite sides of the substratewith respect to each other. The outer surface of the substrate hasdisposed thereon a first connection pad region and first drive or senseelectrodes, the drive or sense electrodes disposed between the substrateand the cover panel. The inner surface of the substrate has disposedthereon a second connection pad region and second drive or senseelectrodes. The second adhesive layer is coupled to the inner surface ofthe substrate. The dielectric layer is coupled to the second adhesivelayer. The FPC is electrically coupled by the first connection padregion to the first drive or sense electrodes. Respective portions ofthe first adhesive layer, the substrate, the second adhesive layer, andthe dielectric layer collectively form a gasket seal around a perimeterof the cover panel. The gasket seal extends in a direction away from thecover panel along an axis substantially perpendicular to the outer andinner surfaces of the substrate. An inner surface of the gasket sealdefines an edge of a channel. A portion of the FPC is disposed withinthe channel and extends through respective openings in each of the firstadhesive layer, the substrate, the second adhesive layer, and thedielectric layer.

In a method embodiment, a method includes forming a connection padregion and drive or sense electrodes on an outer surface of a substrate.A connection pad region and drive or sense electrodes are formed on aninner surface of the substrate. A first adhesive layer adheres to theouter surface of the substrate. A second adhesive layer adheres to theinner surface of the substrate. The method further includes forming achannel extending in a direction substantially perpendicular to theinner and outer surfaces of the substrate, at least in part, by cuttingaway selective portions of the substrate and the first and secondadhesive layers. A portion of a flexible printed circuit (FPC) isinserted into the channel formed. The FPC is bent, such that a firstportion of the FPC is disposed outwardly from the connection pad regionformed on the outer surface of the substrate while a second portion ofthe FPC is disposed within the channel. The method further includeselectrically coupling the FPC to the drive or sense electrodes formed onthe outer surface of the substrate, at least in part, by bonding the FPCto the connection pad region formed on the outer surface of thesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example touch sensor with an example controller.

FIGS. 2A-2C illustrate different views of an example mechanical stack.

FIG. 3A-3C illustrate different views of another example mechanicalstack.

FIG. 4A-4D illustrate different views of an example mechanical stackwith multiple connection pad regions.

FIG. 5A-5C illustrate different views of another example mechanicalstack; and

FIG. 6A-6C illustrate different views of another example mechanicalstack.

FIG. 7 illustrates an example device incorporating a touch sensordisposed on a mechanical stack.

FIGS. 8A and 8B illustrate cross-sectional views of an examplemechanical stack forming a gasket seal and having one or more channelsextending through at least portions of multiple layers of the mechanicalstack.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example touch sensor 10 with an exampletouch-sensor controller 12. Touch sensor 10 and touch-sensor controller12 may detect the presence and location of a touch or the proximity ofan object within a touch-sensitive area of touch sensor 10. Herein,reference to a touch sensor may encompass both the touch sensor and itstouch-sensor controller, where appropriate. Similarly, reference to atouch-sensor controller may encompass both the touch-sensor controllerand its touch sensor, where appropriate. Touch sensor 10 may include oneor more touch-sensitive areas, where appropriate. Touch sensor 10 mayinclude an array of drive and sense electrodes (or an array ofelectrodes of a single type) disposed on one or more substrates, whichmay be made of a dielectric material. Herein, reference to a touchsensor may encompass both the electrodes of the touch sensor and thesubstrate(s) that they are disposed on, where appropriate.Alternatively, where appropriate, reference to a touch sensor mayencompass the electrodes of the touch sensor, but not the substrate(s)that they are disposed on.

An electrode (whether a drive electrode or a sense electrode) may be anarea of conductive material forming a shape, such as for example a disc,square, rectangle, thin line other suitable shape, or suitablecombination of these. One or more cuts in one or more layers ofconductive material may (at least in part) create the shape of anelectrode, and the area of the shape may (at least in part) be boundedby those cuts. In particular embodiments, the conductive material of anelectrode may occupy approximately 100% of the area of its shape. As anexample and not by way of limitation, an electrode may be made of indiumtin oxide (ITO) and the ITO of the electrode may occupy approximately100% of the area of its shape (sometimes referred to as 100% fill),where appropriate. In particular embodiments, the conductive material ofan electrode may occupy substantially less than 100% of the area of itsshape. As an example and not by way of limitation, an electrode may bemade of fine lines of metal or other conductive material (FLM), such asfor example copper, silver, or a copper- or silver-based material, andthe fine lines of conductive material may occupy approximately 5% of thearea of its shape in a hatched, mesh, or other suitable pattern. Herein,reference to FLM encompasses such material, where appropriate. Althoughthis disclosure describes or illustrates particular electrodes made ofparticular conductive material forming particular shapes with particularfills having particular patterns, this disclosure contemplates anysuitable electrodes made of any suitable conductive material forming anysuitable shapes with any suitable fill percentages having any suitablepatterns.

Where appropriate, the shapes of the electrodes (or other elements) of atouch sensor may constitute in whole or in part one or moremacro-features of the touch sensor. One or more characteristics of theimplementation of those shapes (such as, for example, the conductivematerials, fills, or patterns within the shapes) may constitute in wholeor in part one or more micro-features of the touch sensor. One or moremacro-features of a touch sensor may determine one or morecharacteristics of its functionality, and one or more micro-features ofthe touch sensor may determine one or more optical features of the touchsensor, such as transmittance, refraction, or reflection.

A mechanical stack may contain the substrate (or multiple substrates)and the conductive material forming the drive or sense electrodes oftouch sensor 10. As an example and not by way of limitation, themechanical stack includes a first layer of optically clear adhesive(OCA) beneath a cover panel. The cover panel may be clear and made of aresilient material suitable for repeated touching, such as for exampleglass, polycarbonate, or poly(methyl methacrylate) (PMMA). Thisdisclosure contemplates any suitable cover panel made of any suitablematerial. The first layer of OCA is disposed between the cover panel andthe substrate with the conductive material forming the drive or senseelectrodes. The mechanical stack may also include a second layer of OCAand a dielectric layer (which may be made of PET or another suitablematerial, similar to the substrate with the conductive material formingthe drive or sense electrodes). As an alternative, where appropriate, athin coating of a dielectric material may be applied instead of thesecond layer of OCA and the dielectric layer. The second layer of OCAmay be disposed between the substrate with the conductive materialmaking up the drive or sense electrodes and the dielectric layer, andthe dielectric layer may be disposed between the second layer of OCA andan air gap to a display of a device including touch sensor 10 andtouch-sensor controller 12. As an example only and not by way oflimitation, the cover panel may have a thickness of approximately 1 mm;the first layer of OCA may have a thickness of approximately 0.05 mm;the substrate with the conductive material forming the drive or senseelectrodes may have a thickness of approximately 0.05 mm; the secondlayer of OCA may have a thickness of approximately 0.05 mm; and thedielectric layer may have a thickness of approximately 0.05 mm. Althoughthis disclosure describes a particular mechanical stack with aparticular number of particular layers made of particular materials andhaving particular thicknesses, this disclosure contemplates any suitablemechanical stack with any suitable number of any suitable layers made ofany suitable materials and having any suitable thicknesses. As anexample and not by way of limitation, in particular embodiments, a layerof adhesive or dielectric may replace the dielectric layer, second layerof OCA, and air gap described above, with there being no air gap to thedisplay.

One or more portions of the substrate of touch sensor 10 may be made ofpolyethylene terephthalate (PET) or another suitable material. Thisdisclosure contemplates any suitable substrate with any suitableportions made of any suitable material. In particular embodiments, thedrive or sense electrodes in touch sensor 10 may be made of ITO in wholeor in part. In particular embodiments, the drive or sense electrodes intouch sensor 10 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, one or moreportions of the conductive material may be copper or copper-based andhave a thickness of approximately 5 μm or less and a width ofapproximately 10 μm or less. As another example, one or more portions ofthe conductive material may be silver or silver-based and similarly havea thickness of approximately 5 μm or less and a width of approximately10 μm or less. This disclosure contemplates any suitable electrodes madeof any suitable material.

Touch sensor 10 may implement a capacitive form of touch sensing. In amutual-capacitance implementation, touch sensor 10 may include an arrayof drive and sense electrodes forming an array of capacitive nodes. Adrive electrode and a sense electrode may form a capacitive node. Thedrive and sense electrodes forming the capacitive node may come neareach other, but not make electrical contact with each other. Instead,the drive and sense electrodes may be capacitively coupled to each otheracross a space between them. A pulsed or alternating voltage applied tothe drive electrode (by touch-sensor controller 12) may induce a chargeon the sense electrode, and the amount of charge induced may besusceptible to external influence (such as a touch or the proximity ofan object). When an object touches or comes within proximity of thecapacitive node, a change in capacitance may occur at the capacitivenode and touch-sensor controller 12 may measure the change incapacitance. By measuring changes in capacitance throughout the array,touch-sensor controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10.

In a self-capacitance implementation, touch sensor 10 may include anarray of electrodes of a single type that may each form a capacitivenode. When an object touches or comes within proximity of the capacitivenode, a change in self-capacitance may occur at the capacitive node andtouch-sensor controller 12 may measure the change in capacitance, forexample, as a change in the amount of charge needed to raise the voltageat the capacitive node by a pre-determined amount. As with amutual-capacitance implementation, by measuring changes in capacitancethroughout the array, touch-sensor controller 12 may determine theposition of the touch or proximity within the touch-sensitive area(s) oftouch sensor 10. This disclosure contemplates any suitable form ofcapacitive touch sensing, where appropriate.

In particular embodiments, one or more drive electrodes may togetherform a drive line running horizontally or vertically or in any suitableorientation. Similarly, one or more sense electrodes may together form asense line running horizontally or vertically or in any suitableorientation. In particular embodiments, drive lines may runsubstantially perpendicular to sense lines. Herein, reference to a driveline may encompass one or more drive electrodes making up the driveline, and vice versa, where appropriate. Similarly, reference to a senseline may encompass one or more sense electrodes making up the senseline, and vice versa, where appropriate.

Touch sensor 10 may have drive and sense electrodes disposed in apattern on one side of a single substrate. In such a configuration, apair of drive and sense electrodes capacitively coupled to each otheracross a space between them may form a capacitive node. For aself-capacitance implementation, electrodes of only a single type may bedisposed in a pattern on a single substrate. In addition or as analternative to having drive and sense electrodes disposed in a patternon one side of a single substrate, touch sensor 10 may have driveelectrodes disposed in a pattern on one side of a substrate and senseelectrodes disposed in a pattern on another side of the substrate.Moreover, touch sensor 10 may have drive electrodes disposed in apattern on one side of one substrate and sense electrodes disposed in apattern on one side of another substrate. In such configurations, anintersection of a drive electrode and a sense electrode may form acapacitive node. Such an intersection may be a location where the driveelectrode and the sense electrode “cross” or come nearest each other intheir respective planes. The drive and sense electrodes do not makeelectrical contact with each other—instead they are capacitively coupledto each other across a dielectric at the intersection. Although thisdisclosure describes particular configurations of particular electrodesforming particular nodes, this disclosure contemplates any suitableconfiguration of any suitable electrodes forming any suitable nodes.Moreover, this disclosure contemplates any suitable electrodes disposedon any suitable number of any suitable substrates in any suitablepatterns.

As described above, a change in capacitance at a capacitive node oftouch sensor 10 may indicate a touch or proximity input at the positionof the capacitive node. Touch-sensor controller 12 may detect andprocess the change in capacitance to determine the presence and locationof the touch or proximity input. Touch-sensor controller 12 may thencommunicate information about the touch or proximity input to one ormore other components (such one or more central processing units (CPUs))of a device that includes touch sensor 10 and touch-sensor controller12, which may respond to the touch or proximity input by initiating afunction of the device (or an application running on the device).Although this disclosure describes a particular touch-sensor controllerhaving particular functionality with respect to a particular device anda particular touch sensor, this disclosure contemplates any suitabletouch-sensor controller having any suitable functionality with respectto any suitable device and any suitable touch sensor.

Touch-sensor controller 12 may be one or more integrated circuits (ICs),such as for example general-purpose microprocessors, microcontrollers,programmable logic devices or arrays, application-specific ICs (ASICs).In particular embodiments, touch-sensor controller 12 comprises analogcircuitry, digital logic, and digital non-volatile memory. In particularembodiments, touch-sensor controller 12 is disposed on a flexibleprinted circuit (FPC) bonded to the substrate of touch sensor 10, asdescribed below. The FPC may be active or passive, where appropriate. Inparticular embodiments, multiple touch-sensor controllers 12 aredisposed on the FPC. Touch-sensor controller 12 may include a processorunit, a drive unit, a sense unit, and a storage unit. The drive unit maysupply drive signals to the drive electrodes of touch sensor 10. Thesense unit may sense charge at the capacitive nodes of touch sensor 10and provide measurement signals to the processor unit representingcapacitances at the capacitive nodes. The processor unit may control thesupply of drive signals to the drive electrodes by the drive unit andprocess measurement signals from the sense unit to detect and processthe presence and location of a touch or proximity input within thetouch-sensitive area(s) of touch sensor 10. The processor unit may alsotrack changes in the position of a touch or proximity input within thetouch-sensitive area(s) of touch sensor 10. The storage unit may storeprogramming for execution by the processor unit, including programmingfor controlling the drive unit to supply drive signals to the driveelectrodes, programming for processing measurement signals from thesense unit, and other suitable programming, where appropriate. Althoughthis disclosure describes a particular touch-sensor controller having aparticular implementation with particular components, this disclosurecontemplates any suitable touch-sensor controller having any suitableimplementation with any suitable components.

Tracks 14 of conductive material disposed on the substrate of touchsensor 10 may couple the drive or sense electrodes of touch sensor 10 toconnection pads 16, also disposed on the substrate of touch sensor 10.As described below, connection pads 16 facilitate coupling of tracks 14to touch-sensor controller 12. Tracks 14 may extend into or around (e.g.at the edges of) the touch-sensitive area(s) of touch sensor 10.Particular tracks 14 may provide drive connections for couplingtouch-sensor controller 12 to drive electrodes of touch sensor 10,through which the drive unit of touch-sensor controller 12 may supplydrive signals to the drive electrodes. Other tracks 14 may provide senseconnections for coupling touch-sensor controller 12 to sense electrodesof touch sensor 10, through which the sense unit of touch-sensorcontroller 12 may sense charge at the capacitive nodes of touch sensor10. Tracks 14 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, the conductivematerial of tracks 14 may be copper or copper-based and have a width ofapproximately 100 μm or less. As another example, the conductivematerial of tracks 14 may be silver or silver-based and have a width ofapproximately 100 μm or less. In particular embodiments, tracks 14 maybe made of ITO in whole or in part in addition or as an alternative tofine lines of metal or other conductive material. Although thisdisclosure describes particular tracks made of particular materials withparticular widths, this disclosure contemplates any suitable tracks madeof any suitable materials with any suitable widths. In addition totracks 14, touch sensor 10 may include one or more ground linesterminating at a ground connector (which may be a connection pad 16) atan edge of the substrate of touch sensor 10 (similar to tracks 14).

Connection pads 16 may be located along one or more edges of thesubstrate, outside the touch-sensitive area(s) of touch sensor 10. Asdescribed above, touch-sensor controller 12 may be on an FPC. Connectionpads 16 may be made of the same material as tracks 14 and may be bondedto the FPC using an anisotropic conductive film (ACF) or anisotropicconductive paste (ACP). Connection 18 may include conductive lines onthe FPC coupling touch-sensor controller 12 to connection pads 16, inturn coupling touch-sensor controller 12 to tracks 14 and to the driveor sense electrodes of touch sensor 10. In another embodiment,connection pads 16 may be connected to an electro-mechanical connector(such as a zero insertion force wire-to-board connector); in thisembodiment, connection 18 may not need to include an FPC. Thisdisclosure contemplates any suitable connection 18 between touch-sensorcontroller 12 and touch sensor 10.

FIGS. 2A-2C illustrate different views of an example mechanical stack 34a. FIG. 2A shows a longitudinal view of mechanical stack 34 a.Mechanical stack 34 a includes a substrate 26 with conductive material24 a-b forming the drive and sense electrodes of the touch sensor 10,disposed on opposing surfaces of substrate 26. One or more portions ofsubstrate 26 may be made of PET, glass, PMMA, or another suitablematerial, and this disclosure contemplates any suitable substrate madeof any suitable material. In particular embodiments, mechanical stack 34a includes a first adhesive layer 22 a disposed between cover panel 20and substrate 26. Mechanical stack 34 a also includes a second adhesivelayer 22 b and a dielectric layer 28. The second adhesive layer 22 b isdisposed between substrate 26 and dielectric layer 28, and dielectriclayer 28 is disposed between adhesive layer 22 b and an air gap 29 to adisplay 30 of a device including touch sensor 10. Dielectric layer 28may be made of PET or another suitable material. As an example and notby way of limitation, adhesive layers 22 a-b are made from OCA. Asdescribed above, cover panel 20 is made of substantially transparentmaterial, such as for example, glass, PC, or PMMA, and this disclosurecontemplates any suitable cover panel made of any suitable material.

As an example and not by way of limitation, cover panel 20 has athickness of approximately 1 mm; first adhesive layer 22 a has athickness of approximately 0.1 mm; substrate 26 with conductive material24 a-b forming the drive and sense electrodes has a thickness ofapproximately 0.05 mm (including the conductive material forming thedrive and sense electrodes); second adhesive layer 22 b has a thicknessof approximately 0.025 mm; and dielectric layer 28 has a thickness ofapproximately 0.05 mm.

Conductive material 24 a-b forming the drive and sense electrodes may bean area of conductive material that forms a shape, such as for example,a disk, square, rectangle, other suitable shape or suitable combinationof these disposed on a surface of substrate 26. As an example and not byway of limitation, conductive material 24 a-b of an electrode is madefrom a conductive mesh of fine lines of conductive material (such as forexample, carbon nanotubes, gold, aluminum, copper, silver, or copper- orsilver-based material) or other conductive material, and the fine linesof conductive material occupies approximately 10% of the area of itsshape in a hatched or other suitable pattern. As another example, theconductive mesh substantially covers an entire active area of the touchsensor 10. In particular embodiments, conductive material 24 a-b isopaque. Although the fine lines of conductive material 24 a-b areopaque, the combined optical transmissivity of electrodes formed using aconductive mesh is approximately 95% or higher, ignoring a reduction intransmittance due to other factors such as the substantially flexiblesubstrate material 26. In other particular embodiments, the electrodes,tracking, and connection pads of the touch sensor are formed fromconductive material 24 a-b.

In certain embodiments, substrate 26 has connection pads 16 a-b disposedon opposing sides of substrate 26, as shown in FIG. 2A. Connection pads16 a-b define a three-dimensional connection pad region 40 a withinmechanical stack 34 a. FIG. 2C illustrates a top view of mechanicalstack 34 a. In FIG. 2C, the hatched area represents adhesive layers 22a-b, corresponding to a superposition of the shading patterns used foradhesive layers 22 a-b in FIGS. 2A-2B. As shown in FIG. 2C, connectionpad region 40 a extends across the entire width of mechanical stack 34a. Connection pad region 40 a also extends through all layers ofmechanical stack 34 a, as shown in FIG. 2A. In certain embodiments,substrate 26 may have only a single connection pad 16 disposed on asurface of substrate 26, or may have three or more connection pads 16disposed on a surface of substrate 26. This disclosure contemplates anysuitable number of connection pads 16.

As described above, touch-sensor controller 12 may be disposed on anFPC, and the FPC may be bonded to connection pads 16 a-b using ACF orACP. Because substrate 26 has a thickness of 0.05 mm, the weight of theFPC or forces during bonding could place stress on substrate 26 atconnection pad region 40 a, which could bend substrate 26, possiblycausing damage to or breaks in conductive material 24 a-b. In particularembodiments, adhesive layers 22 a-b may extend longitudinally intoportions of connection pad region 40 a in order to provide supportaround connection pads 16 a-b. In certain embodiments, dielectric layer28 co-extends with second adhesive layer 22 b, as illustrated in theexample of FIGS. 2A-2C. In addition to providing support, extendingadhesive layers 22 a-b into portions of connection pad region 40 a mayform a sealing gasket to cover panel 20 for improved resistance tomoisture ingress, which could corrode conductive material 24 a-b.

In FIGS. 2A-2C, for example, first adhesive layer 22 a and secondadhesive layer 22 b both have three extensions into connection padregion 40 a, which appear to overlap when viewed from the perspective ofFIG. 2C: one between connection pad 16 a and connection pad 16 b, onebetween connection pad 16 a and a first outer edge of mechanical stack34 a, and one between connection pad 16 b and the opposite outer edge ofmechanical stack 34 a. In certain other embodiments, adhesive layers 22a-b may extend together into more or fewer portions of connection padregion 40 a. In further embodiments, adhesive layers 22 a-b may extendtogether into certain portions of connection pad region 40 a, but extendseparately into certain other portions of connection pad region 40 a.Alternatively, adhesive layers 22 a-b may extend into entirely separateportions of connection pad region 40 a, only first adhesive layer 22 amay extend into portions of connection pad region 40 a, or only secondadhesive layer 22 b may extend into portions of connection pad region 40a.

FIG. 2B illustrates a transverse cross-sectional view of mechanicalstack 34 a at connection pad region 40 a. Connection pad region 40 a maybe divided into several three-dimensional zones 42-46. Each connectionpad 16 within connection pad region 40 a defines a connection pad zone44, which extends through all layers of mechanical stack 34 a. Asillustrated in FIG. 2B for example, connection pad 16 a definesconnection pad zone 44 a, which occupies roughly the area of connectionpad 16 a and extends through all layers of mechanical stack 34 a.Likewise, connection pad 16 b defines connection pad zone 44 b, whichoccupies roughly the area of connection pad 16 b and extends through alllayers of mechanical stack 34 a. The area between two connection padzones 44 within a connection pad region 40 a defines a central zone 46,which extends through all layers of mechanical stack 34 a. In theexample of FIGS. 2B-2C, central zone 46 is located between connectionpad zone 44 a and connection pad zone 44 b. The area between the outeredge of connection pad region 40 a and a connection pad zone 44 definesan outer zone 42, which extends through all layers of mechanical stack34 a. For example, outer zone 42 a is located between connection padzone 44 a and one outer edge of connection pad region 40 a, and outerzone 42 b is located between connection pad zone 44 b and the oppositeouter edge of the connection pad region 40 a.

In particular embodiments, adhesive layers 22 a-b may extendlongitudinally to one or more zones 42-46 within connection pad region40 a in order to provide support around connection pads 16 a-b. Asillustrated in FIGS. 2B-2C for example, first adhesive layer 22 aextends to outer zone 42 a, central zone 46, and outer zone 42 b; andsecond adhesive layer 22 b also extends to outer zone 42 a, central zone46, and outer zone 42 b. In certain other embodiments, first adhesivelayer 22 a may extend to outer zone 42 a only, outer zone 42 b only,central zone 46 only, outer zone 42 a and central zone 46, outer zone 42b and central zone 46, or any suitable combination of the foregoing.Likewise, in combination with any of the foregoing configurations offirst adhesive layer 22 a, second adhesive layer 22 b may extend toouter zone 42 a only, outer zone 42 b only, central zone 46 only, outerzone 42 a and central zone 46, outer zone 42 b and central zone 46, orany suitable combination of the foregoing. In further embodiments, onlyone of adhesive layers 22 a-b may extend into one or more zones 42-46within connection pad region 40 a.

FIGS. 3A-3C illustrate different views of another example mechanicalstack 34 b. FIG. 3A illustrates a longitudinal view of mechanical stack34 b. FIG. 3B illustrates a transverse cross-sectional view ofmechanical stack 34 b at connection pad region 40 b. FIG. 3C illustratesa top view of mechanical stack 34 b. Mechanical stack 34 b includes asubstrate 26 with conductive material 24 a-b forming the drive and senseelectrodes of the touch sensor 10, disposed on opposing surfaces ofsubstrate 26. In certain embodiments, mechanical stack 34 b includes afirst adhesive layer 22 a, a second adhesive layer 22 b, and adielectric layer 28, as illustrated in FIG. 3A. First adhesive layer 22a is disposed between cover panel 20 and substrate 26; second adhesivelayer 22 b is disposed between substrate 26 and dielectric layer 28, anddielectric layer 28 is disposed between adhesive layer 22 b and an airgap 29 to a display 30 of a device including touch sensor 10.

In certain embodiments, substrate 26 has connection pads 16 a-b disposedon opposing sides of substrate 26, as shown in FIG. 3A. Connection pads16 a-b define a three-dimensional connection pad region 40 b withinmechanical stack 34 b. As described above, connection pad region 40 bextends across the entire width of mechanical stack 34 b, as shown inFIG. 3C, and extends through all layers of mechanical stack 34 b, asshown in FIG. 3A. Connection pad region 40 b may be divided into severalthree-dimensional zones 42-46, which extend through all layers ofmechanical stack 34 b as illustrated in FIGS. 3B-3C: outer zone 42 a,connection pad zone 44 a (defined by connection pad 16 a), central zone46, connection pad zone 44 b (defined by connection pad 16 b), and outerzone 42 b. In certain embodiments, substrate 26 may have only a singleconnection pad 16 disposed on a surface of substrate 26, or may havethree or more connection pads 16 disposed on a surface of substrate 26.This disclosure contemplates any suitable number of connection pads 16.

In the example of FIGS. 3A-3C, adhesive layers 22 a-b extendlongitudinally into several zones 42-46 within connection pad region 40b in order to provide support around connection pads 16 a-b.Specifically, first adhesive layer 22 a extends to outer zone 42 a,central zone 46, connection pad zone 44 b, and outer zone 42 b; andsecond adhesive layer 22 b extends to outer zone 42 a, connection padzone 44 a, central zone 46, and outer zone 42 b. In certain embodiments,dielectric layer 28 co-extends with second adhesive layer 22 b, asillustrated in the example of FIGS. 3A-3C. In this configuration,adhesive is present opposite both connection pads 16 a-b acrosssubstrate 26 (e.g. first adhesive layer 22 a in connection pad zone 44 band second adhesive layer 22 b in connection pad zone 44 a). In FIG. 3C,the hatched area represents adhesive layers 22 a-b, corresponding to asuperposition of the shading patterns used for adhesive layers 22 a-b inFIGS. 3A-3B. In areas where one adhesive layer 22 is present, but theother is not (i.e. connection pad zones 44 a-b), only the shadingpattern for the adhesive layer 22 which is present is depicted.

Using conventional ACF or ACP to bond an FPC to connection pads 16 a-bmay damage or degrade the adhesive opposite connection pads 16 a-b. As aresult, the FPC including touch-sensor controller 12 may be bonded toconnection pads 16 a-b using low-temperature ACF or low-temperature ACP.Low-temperature ACF and ACP generally bond at temperatures belowapproximately 160° C. The configuration of adhesive layers 22 a-bdepicted in FIGS. 3A-3C provides support throughout connection padregion 40 b, including the areas directly opposite connection pads 16a-b. Moreover, in the configuration depicted in FIGS. 3A-3C, the firstadhesive layer 22 a forms a partial sealing gasket at the interfacebetween first adhesive layer 22 a and cover panel 20 to resist moistureingress.

In the example mechanical stacks of FIGS. 2A-2C and FIGS. 3A-3C,connection pads 16 a-b are aligned and together define a singleconnection pad region 40. In certain other embodiments, connection pads16 a-b may be offset, each defining a separate connection pad region 40.FIGS. 4A-4D illustrate different views of an example mechanical stack 34c with multiple connection pad regions 40 c-d. FIG. 4A illustrates alongitudinal view of mechanical stack 34 c. FIG. 4B illustrates atransverse cross-sectional view of mechanical stack 34 c at connectionpad region 40 c.

FIG. 4C illustrates a transverse cross-sectional view of mechanicalstack 34 c at connection pad region 40 d. FIG. 4D illustrates a top viewof mechanical stack 34 c. Mechanical stack 34 c includes a substrate 26with conductive material 24 a-b forming the drive and sense electrodesof the touch sensor 10, disposed on opposing surfaces of substrate 26.In certain embodiments, mechanical stack 34 c includes a first adhesivelayer 22 a, a second adhesive layer 22 b, and a dielectric layer 28, asillustrated in FIG. 4A. First adhesive layer 22 a is disposed betweencover panel 20 and substrate 26; second adhesive layer 22 b is disposedbetween substrate 26 and dielectric layer 28, and dielectric layer 28 isdisposed between adhesive layer 22 b and an air gap 29 to a display 30of a device including touch sensor 10. In certain embodiments, substrate26 has connection pads 16 a-b disposed on opposing sides of substrate26, as shown in FIG. 4A. Connection pads 16 a-b are offset from oneanother, as shown in FIGS. 4A and 4D. Connection pad 16 a defines athree-dimensional connection pad region 40 c within mechanical stack 34c. Connection pad 16 b defines a three-dimensional connection pad region40 d within mechanical stack 34 c. As described above, connection padregions 40 c-d extend across the entire width of mechanical stack 34 c,as shown in FIG. 4D, and extend through all layers of mechanical stack34 c, as shown in FIG. 4A. Although in the example of FIGS. 4A-4D, theoffset between connection pads 16 a-b is sufficiently large thatconnection pad regions 40 c-d are non-overlapping, this disclosurecontemplates any suitable offset between connection pads 16 a-b,including small offsets which would result in overlap between connectionpad regions 40 c-d. Connection pad regions 40 c-d may be divided intoseveral three-dimensional zones 42-44, which extend through all layersof mechanical stack 34 c as illustrated in FIGS. 4B-4D. Connection padregion 40 c is divided into outer zone 42 a, connection pad zone 44 a(defined by connection pad 16 a), and outer zone 42 c. Connection padregion 40 d is divided into outer zone 42 d, connection pad zone 44 b(defined by connection pad 16 b), and outer zone 42 b. In certainembodiments, substrate 26 may have only a single connection pad 16disposed on a surface of substrate 26, or may have three or moreconnection pads 16 disposed on a surface of substrate 26. Thisdisclosure contemplates any suitable number of connection pads 16.

In the example of FIGS. 4A-4D, adhesive layers 22 a-b extendlongitudinally into zones 42 a-d within connection pad regions 40 c-d inorder to provide support around connection pads 16 a-b. Specifically,first adhesive layer 22 a extends to outer zone 42 a and outer zone 42 cof connection pad region 40 c, and to outer zone 42 d, connection padzone 44 b, and outer zone 42 b of connection pad region 40 d; and secondadhesive layer 22 b extends to outer zone 42 a, connection pad zone 44a, and outer zone 42 c of connection pad region 40 c, and to outer zone42 d and outer zone 42 b of connection pad region 40 d. In certainembodiments, dielectric layer 28 co-extends with second adhesive layer22 b, as illustrated in the example of FIGS. 4A-4D. In FIG. 4D, thehatched area represents adhesive layers 22 a-b, corresponding to asuperposition of the shading patterns used for adhesive layers 22 a-b inFIGS. 4A-4C. In areas where one adhesive layer 22 is present, but theother is not (i.e. connection pad zones 44 a-b), only the shadingpattern for the adhesive layer 22 which is present is depicted.

In further embodiments, first adhesive layer 22 a may not extend toconnection pad zone 44 b within connection pad region 40 d and/or secondadhesive layer 22 b may not extend to connection pad zone 44 a withinconnection pad region 40 c. Alternatively, first adhesive layer 22 a mayextend to outer zone 42 a only, outer zone 42 c only, outer zone 42 donly, connection pad zone 44 b only, outer zone 42 b only, or anysuitable combination of the foregoing. Likewise, in combination with anyof the foregoing configurations of first adhesive layer 22 a, secondadhesive layer 22 b may extend to outer zone 42 a only, connection padzone 444 a only, outer zone 42 c only, outer zone 42 d only, outer zone42 b only, or any suitable combination of the foregoing. In certainother embodiments, only one of adhesive layers 22 a-b may extend intoone or more zones 42-44 within connection pad regions 40 c-d.

FIGS. 5A-5C illustrate different views of another example mechanicalstack 34 d. FIG. 5A illustrates a longitudinal view of mechanical stack34 d. FIG. 5B illustrates a transverse cross-sectional view ofmechanical stack 34 d at connection pad region 40 e. FIG. 5C illustratesa top view of mechanical stack 34 d. Mechanical stack 34 d includes asubstrate 26 with conductive material 24 forming the drive and senseelectrodes of the touch sensor 10, disposed on a surface of substrate26. In certain embodiments, mechanical stack 34 d includes an adhesivelayer 22 disposed between cover panel 20 and substrate 26, withconductive material 24 disposed on the surface of substrate 26 nearestadhesive layer 22, as illustrated in FIG. 5A. Substrate 26 is disposedbetween adhesive layer 22 and an air gap 29 to a display 30 of a deviceincluding touch sensor 10 and touch sensor controller 12.

In certain embodiments, substrate 26 has connection pads 16 a-b disposedon a surface of substrate 26, such as the surface nearest adhesive layer22, as shown in FIG. 5A. Connection pads 16 a-b define athree-dimensional connection pad region 40 e within mechanical stack 34d. As described above, connection pad region 40 e extends across theentire width of mechanical stack 34 d, as shown in FIG. 5C, and extendsthrough all layers of mechanical stack 34 d, as shown in FIG. 5A.Connection pad region 40 e may be divided into several three-dimensionalzones 42-46, which extend through all layers of mechanical stack 34 d asillustrated in FIGS. 5B-5C: outer zone 42 a, connection pad zone 44 a(defined by connection pad 16 a), central zone 46, connection pad zone44 b (defined by connection pad 16 b), and outer zone 42 b. In certainother embodiments, substrate 26 may have only a single connection pad 16disposed on a surface, or may have three or more connection pads 16disposed on a surface. This disclosure contemplates any suitable numberof connection pads 16.

In the example of FIGS. 5A-5C, adhesive layer 22 extends longitudinallyinto several zones 42-46 within connection pad region 40 e in order toprovide support around connection pads 16 a-b. Specifically, adhesivelayer 22 extends to outer zone 42 a, central zone 46, and outer zone 42b. In certain other embodiments, adhesive layer 22 may extend to outerzone 42 a only, central zone 46 only, outer zone 42 b only, or anysuitable combination of the foregoing. In FIG. 5C, the shaded arearepresents adhesive layer 22, corresponding to the shading pattern usedfor adhesive layer 22 in FIGS. 5A-5B.

FIGS. 6A-6C illustrate different views of another example mechanicalstack 34 e. FIG. 6A illustrates a longitudinal view of mechanical stack34 e. FIG. 6B illustrates a transverse cross-sectional view ofmechanical stack 34 e at connection pad region 40 f. FIG. 6C illustratesa top view of mechanical stack 34 e. Mechanical stack 34 e includes asubstrate 26 with conductive material 24 a-b forming the drive and senseelectrodes of the touch sensor 10, disposed on a surface of substrate26. In certain embodiments, mechanical stack 34 e includes a firstadhesive layer 22 a, a second adhesive layer 22 b, and a dielectriclayer 28, as illustrated in FIG. 6A. First adhesive layer 22 a isdisposed between cover panel 20 and substrate 26; second adhesive layer22 b is disposed between substrate 26 and dielectric layer 28,dielectric layer 28 is disposed between adhesive layer 22 b and an airgap 29 to a display 30 of a device including touch sensor 10 and touchsensor controller 12, and conductive material 24 is disposed on thesurface of substrate 26 nearest second adhesive layer 22 b.

In certain embodiments, substrate 26 has connection pads 16 a-b disposedon a surface of substrate 26, such as the surface nearest secondadhesive layer 22 b, as shown in FIG. 6A. Connection pads 16 a-b definea three-dimensional connection pad region 40 f within mechanical stack34 e. As described above, connection pad region 40 f extends across theentire width of mechanical stack 34 e, as shown in FIG. 6C, and extendsthrough all layers of mechanical stack 34 e, as shown in FIG. 6A.Connection pad region 40 f may be divided into several three-dimensionalzones 42-46, which extend through all layers of mechanical stack 34 e asillustrated in FIGS. 6B-6C: outer zone 42 a, connection pad zone 44 a(defined by connection pad 16 a), central zone 46, connection pad zone44 b (defined by connection pad 16 b), and outer zone 42 b. In certainother embodiments, substrate 26 may have only a single connection pad 16disposed on a surface, or may have three or more connection pads 16disposed on a surface. This disclosure contemplates any suitable numberof connection pads 16.

In the example of FIGS. 6A-6C, adhesive layers 22 a-b extendlongitudinally into several zones 42-46 within connection pad region 40f in order to provide support around connection pads 16 a-b.Specifically, first adhesive layer 22 a extends to outer zone 42 a,connection pad zone 44 a, central zone 46, connection pad zone 44 b, andouter zone 42 b; and second adhesive layer 22 b extends to outer zone 42a, central zone 46, and outer zone 42 b. In certain embodiments,dielectric layer 28 co-extends with second adhesive layer 22 b, asillustrated in the example of FIGS. 6A-6C. In this configuration,adhesive is present opposite both connection pads 16 a-b acrosssubstrate 26. As a result, the FPC including touch-sensor controller 12may be bonded to connection pads 16 a-b using low-temperature ACF orlow-temperature ACP, which generally bonds at temperatures belowapproximately 160° C. In FIG. 6C, the hatched area represents adhesivelayers 22 a-b, corresponding to a superposition of the shading patternsused for adhesive layers 22 a-b in FIGS. 6A-6B. In areas where adhesivelayer 22 a is present, but adhesive layer 22 b is not (i.e. connectionpad zones 44 a-b), only the shading pattern for adhesive layer 22 a isdepicted.

FIG. 7 illustrates an example device 50 incorporating a touch sensor 10disposed on a mechanical stack 34. As described above, examples ofdevice 50 include a smartphone, a PDA, a tablet computer, a laptopcomputer, a desktop computer, a kiosk computer, a satellite navigationdevice, a portable media player, a portable game console, apoint-of-sale device, another suitable device, a suitable combination oftwo or more of these, or a suitable portion of one or more of these. Inthe example of FIG. 7, device 50 includes a touch sensor 10 implementedusing a mechanical stack 34 and a display 30 underneath the touchsensor. The one or more substrates of the mechanical stack 34 include orhave attached to them tracking areas, which includes tracks 14 providingdrive and sense connections to and from the drive and sense electrodesof the touch sensor. As described above, an electrode pattern of a touchsensor may be made from a conductive mesh using carbon nanotubes, gold,aluminum, copper, silver, or other suitable conductive material. A userof device 50 may interact with device 50 through the touch sensor 10implemented on a mechanical stack 34 described above. As an example andnot by way of limitation, the user interacts with device 50 by touchingthe touch-sensitive area of the touch sensor.

FIGS. 8A and 8B illustrate cross-sectional views of an examplemechanical stack 34 f. In this example, mechanical stack 34 f includes asealing gasket 80 along an outer edge of at least a portion ofmechanical stack 34 f. In addition, mechanical stack 34 f includes oneor more gaps 82 disposed within mechanical stack 34 f. As explainedfurther below, sealing gasket 80 may improve resistance to moistureingress, which could corrode conductive material 24 a-b and/orconnection pads 16 a-b. One or more gaps 82 within mechanical stack 34 fmay facilitate electrically coupling an FPC and/or other suitablecircuitry to connection pads 16 by providing a channel (e.g., channel84) within mechanical stack 34 f through which a portion of an FPCand/or other suitable circuitry may extend. Mechanical stack 34 f may beconfigured to provide mechanical support to substrate 26, which incertain instances may facilitate the electrical coupling of an FPCand/or other suitable circuitry to connection pads 16 a-b. For example,the mechanical support may mitigate the risk of damaging portions ofmechanical stack 34 f (e.g., substrate 26 and/or conductive material 24a-b disposed thereon) when bonding an FPC and/or other suitablecircuitry to connection pads 16 a-b.

In this example, mechanical stack 34 f includes a substrate 26 withconductive material 24 a-b forming the drive and sense electrodes of thetouch sensor 10, disposed on opposing surfaces of substrate 26. Althoughthis example includes conductive material 24 a-b disposed on opposingsurfaces of substrate 26, alternative embodiments may include conductivematerial disposed only on side of substrate 26 (e.g., either 24 a or 24b). For example, a single-sided substrate 26 having conductive material24 a may be configured substantially similar to mechanical stack 34 fshown in FIG. 8A, with the exception that there may be no conductivematerial 24 b disposed on a surface of substrate 26 opposing conductivematerial 24 a. As another example, a single-sided substrate havingconductive material 24 b may be configured substantially similar tomechanical stack 34 f shown by FIG. 8B, with the exception that theremay be no conductive material 24 a disposed on a surface of substrate 26opposing conductive material 24 b.

One or more portions of substrate 26 shown in FIGS. 8A and 8B may bemade of PET, glass, PMMA, or another suitable material, and thisdisclosure contemplates any suitable substrate made of any suitablematerial. In particular embodiments, mechanical stack 34 f includes afirst adhesive layer 22 a disposed between cover panel 20 and substrate26. Mechanical stack 34 f may also include a second adhesive layer 22 bdisposed between substrate 26 and a dielectric layer 28. Dielectriclayer 28 is disposed between adhesive layer 22 b and an air gap 29separating dielectric layer 28 from a display 30 of a device includingtouch sensor 10. Dielectric layer 28 may be made of PET or anothersuitable material. As an example and not by way of limitation, adhesivelayers 22 a-b are made from OCA. As described above, cover panel 20 ismade of substantially transparent material, such as for example, glass,PC, or PMMA, and this disclosure contemplates any suitable cover panelmade of any suitable material.

As an example and not by way of limitation, cover panel 20 shown inFIGS. 8A and 8B has a thickness of approximately 1 mm; first adhesivelayer 22 a has a thickness of approximately 0.1 mm; substrate 26 withconductive material 24 a-b forming the drive and sense electrodes has athickness of approximately 0.05 mm (including the conductive materialforming the drive and sense electrodes); second adhesive layer 22 b hasa thickness of approximately 0.025 mm; and dielectric layer 28 has athickness of approximately 0.05 mm.

Conductive material 24 a-b shown in FIGS. 8A and 8B may form drive andsense electrodes. Conductive material 24 a-b may be an area ofconductive material that forms a shape, such as for example, a disk,square, rectangle, other suitable shape or suitable combination of thesedisposed on a surface of substrate 26. As an example and not by way oflimitation, conductive material 24 a-b of an electrode is made from aconductive mesh of fine lines of conductive material (such as forexample, carbon nanotubes, gold, aluminum, copper, silver, or copper- orsilver-based material) or other conductive material, and the fine linesof conductive material occupies approximately 10% of the area of itsshape in a hatched or other suitable pattern. As another example, theconductive mesh substantially covers an entire active area of the touchsensor 10. In particular embodiments, conductive material 24 a-b isopaque. Although the fine lines of conductive material 24 a-b areopaque, the combined optical transmissivity of electrodes formed using aconductive mesh is approximately 95% or higher, ignoring a reduction intransmittance due to other factors such as the substantially flexiblesubstrate material 26. In other particular embodiments, the electrodes,tracking, and connection pads of the touch sensor are formed fromconductive material 24 a-b.

In certain embodiments, substrate 26 has connection pads 16 a-b disposedon opposing sides of substrate 26, as shown in FIG. 8A. In certainembodiments, substrate 26 may have only a single connection pad 16disposed on a surface of substrate 26, or may have three or moreconnection pads 16 disposed on a surface of substrate 26. Thisdisclosure contemplates any suitable number of connection pads 16.

As described above, touch-sensor controller 12 may be disposed on anFPC, and the FPC may be bonded to connection pads 16 a and/or 16 b usingACF or ACP. One or more gaps 82 within mechanical stack 34 f mayfacilitate electrically coupling an FPC and/or other suitable circuitryto connection pads 16 by providing a channel (e.g., channel 84) withinmechanical stack 34 f through which a portion of an FPC and/or othersuitable circuitry may extend. In certain embodiments, gap 82 a isformed by selectively removing portions of at least adhesive layers 22a-b, substrate 26, and dielectric layer 28, as shown in FIG. 8A. Inparticular embodiments, gap 82 b is formed by selectively removingportions of at least adhesive layers 22 b and dielectric layer 28, asshown in FIG. 8B. The selective removal of mechanical stack 34 f to form82 a and 82 b may be at least partially effected, for example, by sawingmechanical stack 34 f along an axis shown by gaps 82 a and 82 b,respectively. In a particular embodiment, a die cut tool is used toselectively cut away portions of mechanical stack 34 f and form one ormore gaps 82; however, any gaps 82 may be formed using any suitabletool.

In a particular embodiment, the formation of gap 82 a may facilitateaccess to connection pads 16 a for bonding. During a bonding process,for example, an FPC may be inserted into gap 82 a along the z-axis,guided through channel 82 a, and then bonded to an outer surface ofconnection pads 16 a. Additionally or alternatively, the FPC may bebonded to connection pads 16 b. In particular embodiments, the formationof gap 82 a may enable a portion 88 of mechanical stack 34 f to be bentslightly (e.g., in direction of arrow 90), which may facilitateinsertion of an FPC through channel 82. In certain embodiments, cover 20may be coupled to adhesive layer 22 a (e.g., by lamination) aftercompletion of electrical bonding to connection pads 16 a and/orconnection pads 16 b. Although multiple examples are provided herein,the coupling together of the various layers 20-30 mechanical stack 34 fmay occur in any suitable order.

Because substrate 26 has a thickness of 0.05 mm, the weight of the FPCor forces during bonding could place stress on substrate 26 (e.g.,proximate the portion of mechanical stack 34 corresponding to connectionpads 16 a-b), which could bend substrate 26 beyond a threshold thatmight cause damage to or breaks in conductive material 24 a-b. Inparticular embodiments, mechanical support may be provided to mechanicalstack 34 f in a manner that reduces the stress placed on substrate 26during bonding. The mechanical support may be provided, at least inpart, by conforming portions of adhesive layer 22 to the surfaces ofsubstrate 26. The conformity of adhesive layers 22 a-b to substrate 26may include, for example, an extension of a portion of adhesive layers22 a-b beyond conductive material 24 a-b and connection pads 16 a-b in alongitudinal direction (e.g., in a direction along an x-y plane), asshown in FIGS. 8A and 8B. As another example, the conformity of adhesivelayers 22 a-b to substrate 26 may include an extension of adhesivelayers 22 a-b in a direction perpendicular to the longitudinal direction(e.g., in a direction along a y-z plane) and parallel to an axisincluding substrate 26 and connection pad 16 a and/or connection pad 16b, as shown in FIGS. 8A and 8B. As yet another example, the conformityof adhesive layers 22 a-b to substrate 26 may include an extension ofadhesive layers 22 a-b along an edge of and generally coplanar tosubstrate 26, as shown by the portion of gasket 80 defined by volume 86,such that adhesive layers 22 a-b are joined together and form onecontinuous adhesive boundary. In alternative embodiments, however,volume 86 may be a continuous extension of substrate 26 that separatesadhesive layer 22 a from adhesive layer 22 b, such that gasket 80 isformed in part by an edge of substrate 26.

Herein, reference to a computer-readable storage medium encompasses oneor more non-transitory, tangible computer-readable storage mediapossessing structure. As an example and not by way of limitation, acomputer-readable storage medium may include a semiconductor-based orother integrated circuit (IC) (such, as for example, afield-programmable gate array (FPGA) or an application-specific IC(ASIC)), a hard disk, an HDD, a hybrid hard drive (HHD), an opticaldisc, an optical disc drive (ODD), a magneto-optical disc, amagneto-optical drive, a floppy disk, a floppy disk drive (FDD),magnetic tape, a holographic storage medium, a solid-state drive (SSD),a RAM-drive, a SECURE DIGITAL card, a SECURE DIGITAL drive, or anothersuitable computer-readable storage medium or a combination of two ormore of these, where appropriate. Herein, reference to acomputer-readable storage medium excludes any medium that is noteligible for patent protection under 35 U.S.C. §101. Herein, referenceto a computer-readable storage medium excludes transitory forms ofsignal transmission (such as a propagating electrical or electromagneticsignal per se) to the extent that they are not eligible for patentprotection under 35 U.S.C. §101. A computer-readable non-transitorystorage medium may be volatile, non-volatile, or a combination ofvolatile and non-volatile, where appropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Moreover,reference in the appended claims to an apparatus or system or acomponent of an apparatus or system being adapted to, arranged to,capable of, configured to, enabled to, operable to, or operative toperform a particular function encompasses that apparatus, system,component, whether or not it or that particular function is activated,turned on, or unlocked, as long as that apparatus, system, or componentis so adapted, arranged, capable, configured, enabled, operable, oroperative.

What is claimed is:
 1. An apparatus comprising: a cover panel having aninner surface; a first adhesive layer coupled to the cover panel, aperimeter of the first adhesive layer forming at least a portion of agasket seal extending substantially perpendicular to the inner surfaceof the cover panel, an inner surface of the gasket seal defining an edgeof a channel; a substrate coupled to the first adhesive layer, thesubstrate comprising an outer surface having disposed thereon aconnection pad region and drive or sense electrodes, the drive or senseelectrodes disposed between the substrate and the cover panel, at leasta portion of the channel disposed between the gasket seal and theconnection pad region; and a flexible printed circuit (FPC) electricallycoupled by the connection pad region to the drive or sense electrodes, afirst portion of the FPC extending through the channel in a directionsubstantially perpendicular to the inner surface of the cover panel andsubstantially parallel to the inner surface of the gasket seal.
 2. Theapparatus of claim 1, further comprising a second adhesive layerconforming to an inner surface of the substrate at a region opposite theconnection pad region on the outer surface of the substrate, the innerand outer surfaces of the substrate being on opposite sides of thesubstrate with respect to each other.
 3. The apparatus of claim 2,wherein the gasket seal comprises respective portions of the first andsecond adhesive layers.
 4. The apparatus of claim 3, wherein therespective portions of the first and second adhesive layers are coupledto each other.
 5. The apparatus of claim 2, wherein the first and secondadhesive layers form one continuous adhesive layer.
 6. The apparatus ofclaim 2, wherein the gasket seal comprises respective portions of thefirst adhesive layer, the substrate, and the second adhesive layer, thesubstrate being disposed between the first and second adhesive layers.7. The apparatus of claim 6, wherein the channel extends through each ofthe first adhesive layer, the substrate, and the second adhesive layer.8. The apparatus of claim 1, the substrate further comprising an innersurface having disposed thereon a connection pad region and drive orsense electrodes, the inner and outer surfaces of the substrate being onopposite sides of the substrate with respect to each other.
 9. Theapparatus of claim 8, wherein the first adhesive layer substantiallyfills a volume disposed between the cover panel and a portion of theouter surface of the substrate, the portion of the outer surface of thesubstrate and the connection pad region on the inner surface of thesubstrate being disposed on opposite sides of the substrate with respectto each other.
 10. The apparatus of claim 8, wherein the FPC iselectrically coupled by the connection pad region on the inner surfaceof the substrate to the drive or sense electrodes on the inner surfaceof the substrate.
 11. The apparatus of claim 8, wherein a second FPC iselectrically coupled by the connection pad region on the inner surfaceof the substrate to the drive or sense electrodes on the inner surfaceof the substrate.
 12. The apparatus of claim 1, wherein a second portionof the FPC is bonded to the connection pad region on the outer surfaceof the substrate.
 13. The apparatus of claim 12, wherein the FPCcomprises a bend such that the first and second portions of the FPC areat substantially right angles with respect to each other.
 14. Theapparatus of claim 1, wherein the inner surface of the cover panel andthe inner surface of the gasket seal are each substantially disposedalong respective planes that are substantially perpendicular withrespect to each other.
 15. The apparatus of claim 1, wherein the firstadhesive layer comprises an optically clear adhesive (OCA).
 16. A methodcomprising: forming a connection pad region and drive or senseelectrodes on an outer surface of a substrate; forming a connection padregion and drive or sense electrodes on an inner surface of thesubstrate; adhering a first adhesive layer to the outer surface of thesubstrate; adhering a second adhesive layer to the inner surface of thesubstrate; forming a channel extending in a direction substantiallyperpendicular to the inner and outer surfaces of the substrate, at leastin part, by cutting away selective portions of the substrate and thefirst and second adhesive layers; inserting a portion of a flexibleprinted circuit (FPC) into the channel formed, at least in part, byselectively removing portions of the substrate and the first and secondadhesive layers; bending the FPC, such that a first portion of the FPCis disposed outwardly from the connection pad region formed on the outersurface of the substrate and a second portion of the FPC is disposedwithin the channel; and electrically coupling the FPC to the drive orsense electrodes formed on the outer surface of the substrate, at leastin part, by bonding the FPC to the connection pad region formed on theouter surface of the substrate.
 17. The method of claim 16, whereinselectively removing portions of the substrate and the first and secondadhesive layers comprises cutting through the substrate and the firstand second adhesive layers.
 18. The method of claim 16, furthercomprising coupling a cover panel to the first adhesive layer usingadhesion of the first adhesive layer.
 19. The method of claim 16,further comprising electrically coupling the FPC to the drive or senseelectrodes formed on the inner surface of the substrate, at least inpart, by bonding the FPC to the connection pad region formed on theinner surface of the substrate.
 20. An apparatus comprising: a coverpanel having an inner surface; a first optically clear adhesive layercoupled to the cover panel, a substrate coupled to the first adhesivelayer, the substrate comprising: an outer surface having disposedthereon a first connection pad region and first drive or senseelectrodes, the drive or sense electrodes disposed between the substrateand the cover panel; an inner surface having disposed thereon a secondconnection pad region and second drive or sense electrodes, the outerand inner surfaces of the substrate being on opposite sides of thesubstrate with respect to each other; a second adhesive layer coupled tothe inner surface of the substrate; a dielectric layer coupled to thesecond adhesive layer; and a flexible printed circuit (FPC) electricallycoupled by the first connection pad region to the first drive or senseelectrodes; wherein respective portions of the first adhesive layer, thesubstrate, the second adhesive layer, and the dielectric layercollectively form a gasket seal around a perimeter of the cover panel,the gasket seal extending in a direction away from the cover panel alongan axis substantially perpendicular to the outer and inner surfaces ofthe substrate, an inner surface of the gasket seal defining an edge of achannel; and wherein a portion of the FPC is disposed within the channeland extends through respective openings in each of the first adhesivelayer, the substrate, the second adhesive layer, and the dielectriclayer.